The present invention relates to a lead frame and a semiconductor device, and more particularly to a technique which is applicable to a lead frame having multi-leads and a semiconductor device using the lead frame.
In the production of a semiconductor device, such as an LSI, more complicated circuits are being fabricated and the number and type of functions are also increasing with improvement in the degree of integration. Because of the ability to provide increased functions, the semiconductor device has come to require more external terminals, and thus, the numbers of pad electrodes provided on a semiconductor chip and the number of leads that form the external terminals of a semiconductor device have increased in a corresponding manner. For example, the number of external terminals has reached the hundreds in a logic semiconductor device. An example of such a multi-lead semiconductor device is a quad flat package (QFP) type semiconductor device. Since a plurality of leads are provided on all four sides of a sealing body for sealing a semiconductor chip in the QFP type semiconductor device, such a device is suitable for forming multi-leads in that the total spacing around the semiconductor device can be utilized effectively when the semiconductor device is packaged on a packaging substrate.
A lead frame of the type used for the assembling of such a QFP type semiconductor device is disclosed in "VLSI Packaging Technique (the first volume)" issued on May 31, 1993, pp. 155 to 164, and in particular an example of the pattern is shown on p157 and p159.
Further, since the number of elements formed on a semiconductor chip has been increased by means of the above-mentioned refinement and since these elements are operated at a higher speed, the generation of heat from the semiconductor chip has also increased. A semiconductor device in which heat radiation performance has been improved for the purpose of coping with this problem using a heat spreader is described in, for example, "VLSI Packaging Technique (the last volume)" pp. 200 to 203. In this semiconductor device, the heat radiation performance of the semiconductor device is improved by installing a heat spreader on a semiconductor chip.